org.bouncycastle.crypto.modes

Class SICBlockCipher

java.lang.Object

org.bouncycastle.crypto.DefaultMultiBlockCipher

org.bouncycastle.crypto.StreamBlockCipher

org.bouncycastle.crypto.modes.SICBlockCipher

All Implemented Interfaces:

BlockCipher, CTRModeCipher, MultiBlockCipher, SkippingCipher, SkippingStreamCipher, StreamCipher

public class SICBlockCipher
extends StreamBlockCipher
implements CTRModeCipher

Implements the Segmented Integer Counter (SIC) mode on top of a simple block cipher. This mode is also known as CTR mode.

With an IV shorter than the block size, the counter occupies the remaining low bytes and running past its range throws an IllegalStateException. With a full-block IV the whole block is the counter; the advance since init is bounded at 2^64 blocks (the widest range getPosition()/skip arithmetic can represent), past which the same exception is thrown.

Constructor Summary

Constructors

Constructor and Description
SICBlockCipher(BlockCipher c) Deprecated. use newInstance() method.

Method Summary

Modifier and Type	Method and Description
protected byte	calculateByte(byte in)
java.lang.String	getAlgorithmName() Return the name of the algorithm the cipher implements.
int	getBlockSize() Return the block size for this cipher (in bytes).
long	getPosition() Return the current "position" of the cipher
void	init(boolean forEncryption, CipherParameters params) Initialise the cipher.
static CTRModeCipher	newInstance(BlockCipher cipher) Return a new SIC/CTR mode cipher based on the passed in base cipher
int	processBlock(byte[] in, int inOff, byte[] out, int outOff) Process one block of input from the array in and write it to the out array.
int	processBytes(byte[] in, int inOff, int len, byte[] out, int outOff) process a block of bytes from in putting the result into out.
void	reset() Reset the cipher.
long	seekTo(long position) Reset the cipher and then skip forward to a given position.
long	skip(long numberOfBytes) Skip numberOfBytes forwards, or backwards.

Methods inherited from class org.bouncycastle.crypto.StreamBlockCipher

getUnderlyingCipher, returnByte

Methods inherited from class org.bouncycastle.crypto.DefaultMultiBlockCipher

getMultiBlockSize, processBlocks

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Methods inherited from interface org.bouncycastle.crypto.modes.CTRModeCipher

getUnderlyingCipher

Methods inherited from interface org.bouncycastle.crypto.MultiBlockCipher

getMultiBlockSize, processBlocks

Methods inherited from interface org.bouncycastle.crypto.StreamCipher

returnByte

Constructor Detail

SICBlockCipher

@Deprecated
public SICBlockCipher(BlockCipher c)

Deprecated. use newInstance() method.

Basic constructor.

Parameters:

c - the block cipher to be used.

Method Detail

newInstance

public static CTRModeCipher newInstance(BlockCipher cipher)

Return a new SIC/CTR mode cipher based on the passed in base cipher

Parameters:

cipher - the base cipher for the SIC/CTR mode.

init

public void init(boolean forEncryption,
                 CipherParameters params)
          throws java.lang.IllegalArgumentException

Description copied from interface: BlockCipher

Initialise the cipher.

Specified by:

init in interface BlockCipher

Specified by:

init in interface StreamCipher

Parameters:

forEncryption - if true the cipher is initialised for encryption, if false for decryption.

params - the key and other data required by the cipher.

Throws:

java.lang.IllegalArgumentException - if the params argument is inappropriate.

getAlgorithmName

public java.lang.String getAlgorithmName()

Description copied from interface: BlockCipher

Return the name of the algorithm the cipher implements.

Specified by:

getAlgorithmName in interface BlockCipher

Specified by:

getAlgorithmName in interface StreamCipher

Returns:

the name of the algorithm the cipher implements.

getBlockSize

public int getBlockSize()

Description copied from interface: BlockCipher

Return the block size for this cipher (in bytes).

Specified by:

getBlockSize in interface BlockCipher

Returns:

the block size for this cipher in bytes.

processBlock

public int processBlock(byte[] in,
                        int inOff,
                        byte[] out,
                        int outOff)
                 throws DataLengthException,
                        java.lang.IllegalStateException

Description copied from interface: BlockCipher

Process one block of input from the array in and write it to the out array.

Specified by:

processBlock in interface BlockCipher

Parameters:

in - the array containing the input data.

inOff - offset into the in array the data starts at.

out - the array the output data will be copied into.

outOff - the offset into the out array the output will start at.

Returns:

the number of bytes processed and produced.

Throws:

DataLengthException - if there isn't enough data in input , or space in out.

java.lang.IllegalStateException - if the cipher isn't initialised.

processBytes

public int processBytes(byte[] in,
                        int inOff,
                        int len,
                        byte[] out,
                        int outOff)
                 throws DataLengthException

Description copied from interface: StreamCipher

process a block of bytes from in putting the result into out.

Specified by:

processBytes in interface StreamCipher

Overrides:

processBytes in class StreamBlockCipher

Parameters:

in - the input byte array.

inOff - the offset into the in array where the data to be processed starts.

len - the number of bytes to be processed.

out - the output buffer the processed bytes go into.

outOff - the offset into the output byte array the processed data starts at.

Returns:

the number of bytes produced - should always be len.

Throws:

DataLengthException - if the output buffer is too small.

calculateByte

protected byte calculateByte(byte in)
                      throws DataLengthException,
                             java.lang.IllegalStateException

Specified by:

calculateByte in class StreamBlockCipher

Throws:

DataLengthException

java.lang.IllegalStateException

reset

public void reset()

Description copied from interface: BlockCipher

Reset the cipher. After resetting the cipher is in the same state as it was after the last init (if there was one).

Specified by:

reset in interface BlockCipher

Specified by:

reset in interface StreamCipher

skip

public long skip(long numberOfBytes)

Description copied from interface: SkippingCipher

Skip numberOfBytes forwards, or backwards.

Specified by:

skip in interface SkippingCipher

Parameters:

numberOfBytes - the number of bytes to skip (positive forward, negative backwards).

Returns:

the number of bytes actually skipped.

seekTo

public long seekTo(long position)

Description copied from interface: SkippingCipher

Reset the cipher and then skip forward to a given position.

Specified by:

seekTo in interface SkippingCipher

Parameters:

position - the number of bytes in to set the cipher state to.

Returns:

the byte position moved to.

getPosition

public long getPosition()

Description copied from interface: SkippingCipher

Return the current "position" of the cipher

Specified by:

getPosition in interface SkippingCipher

Returns:

the current byte position.